Clamp Systems and Methods for Pile Drivers and Extractors

ABSTRACT

A clamp member for use in securing a vibratory device to a pile comprises a structural portion and a surface layer. The structural portion defines peaks and valleys. The surface layer is formed on the structural portion and defines an engaging surface. The surface layer defining a thickness dimension of at least approximately 0.0025 inches and a grit of at least approximately 180 Emery.

RELATED APPLICATIONS

This application (Attorney's Ref. No. P217360) is a continuation of U.S.patent application Ser. No. 13/116,919 filed May 26, 2011.

U.S. patent application Ser. No. 13/116,929 is a continuation of U.S.patent application Ser. No. 12/772,335 filed May 3, 2010, now U.S. Pat.No. 7,950,877, which issued May 31, 2011.

U.S. patent application Ser. No. 12/772,335 is a continuation of U.S.patent application Ser. No. 11/294,141, filed Dec. 5, 2005, now U.S.Pat. No. 7,708,499, which issued May 4, 2010.

U.S. patent application Ser. No. 11/294,141 claims benefit of U.S.Provisional Application Ser. No. 60/641,289 filed Jan. 3, 2005.

The contents of all related applications listed above are incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to methods and apparatus for insertingrigid members into or extracting rigid members from the earth and, moreparticularly, to clamp systems and methods that attach a piledriver/extractor to a pile to be driven and/or extracted.

BACKGROUND

For certain construction projects, rigid members, such as piles, anchormembers, caissons, sheet pile barriers, and mandrels for inserting wickdrain material, must be placed into the earth. The term “piles” will beused herein to refer to the rigid members typically driven into theearth during construction projects. It is well-known that such rigidmembers may often be driven into or extracted from the earth withoutexcavation by applying a driving or extracting force on an upper end ofthe pile.

When applying a downward driving force to a pile, it is not necessary,although perhaps desirable, to clamp the pile driver to the pile.However, when a pile is extracted from the earth, a clamp system must beused to transmit an upward extracting force to the pile to pull the pilefrom the earth. In addition, during both pile driving and pileextracting, a reciprocating vibratory force, typically up and down, maybe applied in addition to the driving or pulling force. The use ofvibratory forces also requires a clamp system to ensure that thevibratory forces are effectively transmitted to the pile.

A clamp system typically comprises first and second clamp members thatengage the pile. A clamping force may be applied to one or both of theclamp members such that the pile or a portion of the pile is securelygripped between the clamp members. The clamp members may be contoured toaccommodate the shape of the pile or portion of the pile to be gripped.The clamp members may be otherwise textured in some form to increasefriction between the clamp members and the pile.

A primary point of failure of a pile driving or extracting system iswhen the driving, pulling, and/or driving forces are not adequatelytransmitted to the pile. The need thus exists for improved clamp systemsfor pile extractors and for pile drivers and extractors that employvibratory forces.

SUMMARY

The present invention may be embodied as a clamp member for use insecuring a vibratory device to a pile comprises a structural portion anda surface layer. The structural portion defines peaks and valleys. Thesurface layer is formed on the structural portion and defines anengaging surface. The surface layer defining a thickness dimension of atleast approximately 0.0025 inches and a grit of at least approximately180 Emery.

The present invention may also be embodied as a method of forming aclamp member for clamping a vibratory device to a pile comprising thefollowing steps. A clamp member comprising peaks and valleys isprovided. A surface layer is formed on the peaks and valleys of theclamp member such that the surface layer defines an engaging surface.The surface layer defines a thickness dimension of at leastapproximately 0.0025 inches and a grit of at least approximately 180Emery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of one example embodiment of a clampsystem of the present invention;

FIG. 2 is a bottom plan view of the clamp system of FIG. 1; and

FIGS. 3 and 4 are side, elevation sectional views of a clamp member ofthe present invention before and after, respectively, application of asurface layer.

DETAILED DESCRIPTION

Referring to FIG. 1 of the drawing, depicted at 20 therein is a clampassembly constructed in accordance with, and embodying, the principlesof the present invention. The clamp assembly 20 is adapted to beconnected to a vibratory device (not shown) and engages a pile 22 suchthat vibratory forces generated by the vibratory device are transmittedto the pile 22. The present invention is of particular significance inthe context of a clamp assembly for sheet piles such as the clampassembly 20 depicted and described herein, but a clamp assemblyconstructed in accordance with the present invention can be adapted toengage piles of different shapes and materials as will generally bedescribed below.

The clamp assembly 20 comprises first and second clamp members 30 and32. The first clamp member 30 is fixed relative to a clamp frame 34. Thesecond clamp member 32 is mounted on an actuator 36 supported by theclamp frame 34. The actuator 36, which is operated by a hydraulic system(not shown), displaces the second clamp member 32 relative to the clampframe 34 and thus relative to the first clamp member 30. The first clampmember 30 and the actuator 36 are supported by the clamp frame 34 suchthat the actuator 36 moves the second clamp member 32 towards and awayfrom the first clamp member 30. When the clamp assembly 20 is arrangedsuch that the pile 22 is in a clamp space 40 (FIG. 2) between the firstand second clamp members 30 and 32, operation of the actuator 36 causesthe pile 22 to be clamped between the clamp members 30 and 32 as shownin FIG. 1.

The first and second clamp members 30 and 32 define first and secondengaging surfaces 50 and 52, respectively. The example second clampmember 32 is depicted in further detail in FIG. 4 of the drawing. FIG. 4illustrates that the second engaging surface 52 defines peaks 54 andvalleys 56 and is defined by a surface layer 60. The first engagingsurface 50 may optionally be defined by a similar surface layer formedon the first clamp member 30.

To fabricate the example second clamp member 32, FIG. 3 illustrates thatthe second clamp member 32 is originally constructed in a generallyconventional manner in a pre-coated form 32 a. In the pre-coated form 32a, the second clamp member 32 defines an uncoated surface 52 a. Thesurface layer 60 is deposited or otherwise formed on the uncoatedsurface 52 a to create the second engaging surface 52 of the secondclamp member 32. The surface layer 60 is formed using a carbide alloycoating that is sprayed or otherwise deposited on the uncoated surface52 a. One example process for forming the surface layer 60 is marketedunder the brand name CARBINITE Metal Coatings. Other processes forapplying metal coatings similar to the CARBINITE process may be usedinstead or in addition. The surface layer 60 defines a “build-up”dimension generally corresponding to the thickness “t” of the layer 60and also a texture or “grit” that generally defines the friction of thesecond engaging surface 52. The thickness “t” of the surface layer 60 istypically within a first preferred range of 0.006″ and 0.017″, may bewithin a second preferred range of 0.0025″ and 0.017″, and in any eventis within a third preferred range of at least 0.0025″. The grit of thesurface layer is typically within a first range of substantially between100 Emery and 36 Emery, may be within a second preferred range ofsubstantially between 180 Emery and 36 Emery, and in any event should bewithin a third preferred range of at least 180 Emery.

The exact thickness “t” and grit of the surface layer 60 should bedetermined based on the character of the pile being driven. With theexample metal sheet pile 22, the grit is preferably within approximately180 Emery and 100 Emery. For a clamp assembly that will be used toextract a wooden pile that is coated with slime, barnacles, and/or thelike, the grit is preferably greater than 60 Emery to enhance friction.For a plastic sheet pile, the grit is preferably in the range ofapproximately smooth to 180 Emery to reduce damage to the plasticmaterial from which the pile is made.

The thickness “t” can also be increased to increase the wear resistanceof the second engaging surface 52. For example, the pre-coated form 32 aof the second clamp member 32 may be made of relatively soft materialthat is inexpensive and easy to machine. The surface layer 60 may beapplied by building up the thickness “t” thereof using severalapplications of the coating material to increase the thickness of thesurface layer 60 on the pre-coated second clamp member 32 a and thusprotect the engaging surface 52.

From the foregoing, it should be clear that the present invention may beembodied in forms other than the form described above. The above-described embodiment is therefore to be considered in all respectsillustrative and not restrictive.

What is claimed is:
 1. A clamp assembly for use in securing a vibratorydevice that generates vibratory forces to a pile comprising: first andsecond clamp members, where each of the clamp members comprises astructural portion defining peaks and valleys; a surface layer is formedon each of the structural portions, where the surface layer defines anengaging surface, the surface layer defining a thickness dimension of atleast 0.0025 inches; and a grit of at least 180; and a hydraulicactuator for displacing the second clamp member relative to the firstclamp member such that the engaging surfaces of the first and clampmembers engage the pile to transmit at least the vibratory forcesgenerated by the vibratory device to the pile.
 2. A clamp assembly asrecited in claim 1, in which the surface layer is formed of carbidealloy material.
 3. A clamp assembly as recited in claim 1, in which thesurface layer defines a thickness dimension of substantially between0.0025 inches and 0.017 inches.
 4. A clamp assembly as recited in claim1, in which the surface layer defines a thickness dimension ofsubstantially between 0.006 inches and 0.017 inches.
 5. A clamp assemblyas recited in claim 2, in which the surface layer defines a thicknessdimension of substantially between 0.0025 inches and 0.017 inches.
 6. Aclamp assembly as recited in claim 2, in which the surface layer definesa thickness dimension of substantially between 0.006 inches and 0.017inches.
 7. A clamp assembly as recited in claim 1, in which the surfacelayer defines a grit of substantially between 180 and
 36. 8. A clampassembly as recited in claim 1, in which the surface layer defines agrit of substantially between 100 and
 36. 9. A clamp assembly as recitedin claim 2, in which the surface layer defines a grit of substantiallybetween 180 and
 36. 10. A clamp assembly as recited in claim 2, in whichthe surface layer defines a grit of substantially between 100 and 36.11. A clamp assembly as recited in claim 1, in which the surface layercomprises at least one coating layer of coating material.
 12. A clampassembly as recited in claim 11, in which the surface layer comprises aplurality of coating layers of coating material.
 13. A clamp assembly asrecited in claim 2, in which the surface layer is formed by at least onecoating layer of coating material.
 14. A clamp assembly as recited inclaim 13, in which the surface layer is formed by a plurality of coatinglayers of coating material.